What textures i should bake to have a game ready model?
Depends on what you want to crate. And what engine you use.
You can use every single type to create a very realisitc and good looking model, but you need to know what your limits are. The more textures you use the more textures need to get loaded into the RAM. So when you want to make a game with many meshes it is best adviced to either only use the important textures or look how important the mesh is when it comes to the camera for example. Closer meshes should have more important textures than meshes that aren't really visible. 

So choose for yourself what your model needs. You don't need to bake out metallic when you've got a piece of cloth.